This is the slippery slope fallacy and people in tech seem to love this argument. And you can argue in whichever direction you want with it.

For example, "unfettered Internet access is just a series of tubes (shout out to Ted Stevens for that one) for pedophiles to rape your children." So now what? Is it your hyperbole against mine?

The problem is that people are operating under a myth that they have anonymity. You don't. You're one subpoena away from being unmasked online and individuals can do it (eg [1]). When governments do it, they can do it in secret. National Security Letters, pen registers, FISA warrants, etc.

So the idea that "age verification is the first step to a more comprehensive" is flawed in both logical construction (being a fallacy) and that ship has already sailed.

[1]: https://chambers.com/articles/internet-harassment-lawyer